This invention relates generally to the separation of fluids by selective permeation and, more particularly, to permeators of the type having a bundle of hollow fibers as the membrane.
It is know that the fibers in such a permeator can be either double-ended (DE) or single-ended (SE), the difference being that DE fibers are open at each end of the fiber bundle whereas SE fibers reverse at one end and open through a tube sheet at the other end. DE permeators are shown in U.S. Pat. No. 3,953,334 to Brun et al. Channelled end plates and multiple manifolds for the discharge of a permeate must be provided at each end of the permeator. A typical SE permeator is marketed by the assignee of the present invention under the trademark PERMASEP.RTM.. An advantage of such a permeator is the minimum number of external fittings and their location in end plates, all of which lead to lower costs for associated piping and installation. However, as with all SE permeators, there is a rather high drop in pressure down the bores of the fibers and a consequent reduction in the throughput of permeate below what could be expected in the absence of such a pressure drop.